A detail of a Palestinian farmer plowing his vineyard. A careful look will reveal the green weeds and also the vines that are growing along the ground. Notice how the stalk of the vine above the rump of the donkey is propped up to assist its growth.
The farmers will carefully plow their vineyards to keep the weeds from growing, for they want the moisture in the soil to go to the vines rather than to the weeds. In addition, as the summer progresses, the harden lumps of plowed soil do provide a measure of insulation to keep the soil cool and moist during the summer months.